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Climate in Byron · NOAA 1991–2020 normals

Byron’s winters are colder and snowier than most of the U.S.

A typical July afternoon reaches 81°, a January night drops to 6°, and about 44 inches of snow falls in a normal winter.

Colder January nights than 98% of U.S. towns#149 coldest of 270 in MN
More snow than 78% of U.S. towns#166Snowiest  of 267 in MN
All MN rankings →

A year in Byron at a glance

Each month’s typical high and low, and what it brings.

Jan23°6° 9" snow
Feb27°10° 10" snow
Mar40°22° 9" snow
Apr56°34°
May68°46° Last frost ~May 121 day 90°+
Jun78°56° 2 days 90°+Wettest
Jul81°60° 3 days 90°+
Aug79°57° 1 day 90°+
Sep72°49° First frost ~Sep 281 day 90°+
Oct58°36°
Nov now42°25°
Dec28°13° 13" snow

What stands out about Byron’s climate

Compared with towns across the U.S., with Byron’s place in Minnesota beside it.

A normal year

What a year in Byron feels like

Typical highs and lows by season and by month, from NOAA’s 30-year normals.

Winter
26° / 9°
12 days with 1"+ of snow
Spring
54° / 34°
Last frost around May 12
Summer
79° / 58°
8 days reach 90°
Fall
57° / 37°
First frost around Sep 28
Best months to be outsideMayJunJulAugSepHighs of 62–84° and lows of 40° or more
Frost, heat & the growing season

About 139 frost-free days a year

In half of years the last 32° night comes by May 12 and the first by September 28. Frost and day counts come from NOAA’s station at Byron 4north, MN, 4 miles from the town’s center, 160 ft lower.

176
nights at or below 32° in a normal year
42nd most of 270 in Minnesota
More freezing nights than 97% of U.S. towns
35
nights at or below 0°
81st most of 270 in Minnesota
More nights at or below 0° than all but 187 U.S. towns
8
days that reach 90°
117th fewest of 270 in Minnesota
Fewer 90° days than 82% of U.S. towns
0
days that reach 100°
None in a normal year
4bUSDA zone
Plant hardiness zone 4b

The 2023 USDA map puts Byron’s center in zone 4b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −22°. Plant labels use the zone; frost dates tell you when to plant.

Freezing nights by month

Average nights at or below 32°

31
JFMAMJJASOND

90° days by month

Average days at 90° or more

3.4
JFMAMJJASOND
Rain & snow

About 44 inches of snow a winter

Snow, measured at Byron 4north, MN, falls mostly in December. Precipitation (rain plus melted snow) adds up to 36 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 111 days a year.

36"
Rain + melted snow a year
257th driest of 270 in Minnesota
Drier than 75% of U.S. towns
44"
Snow in a normal winter
166th snowiest of 267 in Minnesota
More snow than 78% of U.S. towns
88 days
With 1"+ of snow on the ground
136th most of 204 in Minnesota
More days with snow on the ground than 93% of U.S. towns

Rain + melted snow by month

Inches of water

5.4"
JFMAMJJASOND

Snowfall by month

Inches of snow

13"
JFMAMJJASOND
Heating & cooling

Heating and cooling a home in Byron

95% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.

8,328 heating degree daysMore heating than 98% of U.S. towns
442 cooling degree daysLess cooling than 89% of U.S. towns

Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Byron 4north, MN.

Living here

Living with Byron’s climate

What the numbers mean for a garden, a free afternoon and a bad-weather day.

The garden window

139 frost-free days in zone 4b. The last frost comes by May 12 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 28.

Get outside

Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 1.0 miles of trails are waiting.

Parks & trails →
Storms and extremes

Of the yearly building losses FEMA expects in Byron from natural hazards, river flooding is the largest share (34%); heat waves, cold waves, winter storms and ice storms together are 38%. Normals are averages; the hazards page covers the extremes.

Natural hazards →
Next door

Byron and its neighbors

Every town next door is within a degree of Byron in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.

Rochester: January low 6°, July high 82°Mantorville Township: January low 5°, July high 81°Cascade Township: January low 6°, July high 82°Salem Township: January low 6°, July high 81°New Haven Township: January low 6°, July high 81°Kalmar Township: January low 6°, July high 81°Byron: January low 6°, July high 81°ByronKalmar Township
ColderMilder5° to 6°
Byron5.7°
Kalmar Township5.7° about the same

Climates most like Byron’s, farther away

TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.

TownJan. lowJuly highPrecip.Snow
Byron, MN6°81°36"44"
Hull, WI7°81°33"49"
Peru, NY9°80°35"50"
Colchester, VT10°81°38"50"
Hanover, NH9°82°39"61"

Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.

Then and now

Warmer than it used to be

The last 30 years in Byron averaged 1.3° warmer than the 1900s. The biggest change is in December (+3.2°).

+1.3°1991–2020 vs. 1901–2000

A smaller shift than in 56% of U.S. towns.

Winter+2.6°now 18°, was 15°
Spring+1.0°now 44°, was 43°
Summer+0.3°now 68°, was 68°
Fall+1.1°now 47°, was 46°

Change by month

JanFebMarAprMayJunJulAugSepOctNovDec

The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.

Compared with other towns

How Byron compares

Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Byron’s place among Minnesota’s.

Summer heat81° July high
Cooler July afternoons than 89% of U.S. towns49th coolest of 270 in Minnesota
Winter cold6° January low
Colder January nights than 98% of U.S. towns149th coldest of 270 in Minnesota
Precipitation36" a year
Drier than 75% of U.S. towns257th driest of 270 in Minnesota
Snow44" a winter
More snow than 78% of U.S. towns166th snowiest of 267 in Minnesota
Hot days8 days at 90°+
Fewer 90° days than 82% of U.S. towns117th fewest of 270 in Minnesota
Freezing nights176 a year
More freezing nights than 97% of U.S. towns42nd most of 270 in Minnesota
Growing season139 frost-free days
A shorter frost-free season than 96% of U.S. towns20th shortest of 269 in Minnesota
Month by month

Byron weather by month

Highs, lows and precipitation from NOAA’s grid at Byron’s center; snow, wet days and snow on the ground from Byron 4north, MN. 1991–2020 normals.

MonthHighLowRain + meltSnowWet daysSnow on ground30-yr range
January23°6°1.0"8.8"7254° – 28°
February27°10°1.0"9.6"6256° – 31°
March40°22°2.0"8.8"81623° – 48°
April56°34°3.5"1.2"10134° – 52°
May68°46°4.6"0.6"13051° – 64°
June78°56°5.4"0.0"14063° – 72°
July81°60°4.4"0.0"11064° – 76°
August79°57°4.4"0.0"11063° – 73°
September72°49°3.7"0.0"10053° – 66°
October58°36°2.5"0.1"9041° – 53°
November42°25°1.8"2.8"6224° – 45°
December28°13°1.3"12.5"7196° – 30°
Year54°34°35.7"44.4"11188
Year to year

How much a month can swing

A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 23° to 48°. June is the most reliable, staying within 9°.

Coldest to warmest month in 30 yearsNormal
Sources

Where Byron’s numbers come from

Normals are 30-year averages, not a forecast. How TownRatings reads climate data →

  • Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Byron’s center.
  • Snow: Byron 4north, MN.
  • Frost, freezing nights, 90° and 100° days, heating and cooling: Byron 4north, MN, 4 miles from the town’s center, 160 ft lower; the nearest station that passes our checks for distance, height and agreement with the grid.
  • Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
  • Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
  • Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).

Common questions about Byron’s climate

What is the weather like in Byron?

A typical July afternoon reaches 81°, a January night drops to 6°, and about 44 inches of snow falls in a normal winter. Colder January nights than 98% of U.S. towns; cooler July afternoons than 89% of U.S. towns.

How cold does it get in Byron in winter?

January nights average 6°. About 176 nights a year reach 32° or below and 35 reach 0° or below. In the coldest January of the last 30 years the month averaged 4°.

How much snow does Byron get?

About 44 inches in a normal winter at Byron 4north, MN, most of it in December, with snow on the ground about 88 days a year.

How hot does it get in Byron?

July, with a typical high of 81° and a low of 60°. About 8 days a year reach 90° (Byron 4north, MN).

When is the first and last frost in Byron?

In half of years the last spring frost (32°) comes by May 12 and the first fall frost by September 28, about 139 frost-free days, at Byron 4north, MN.

What growing zone is Byron in?

Zone 4b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −22°.

What is the best time of year to visit Byron?

By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.

Is Byron getting warmer?

Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 56% of U.S. towns.

Neighbors talk weather

Gardens, snow, and the best days of the year in Byron.

Town Square →
Ask your neighbors

Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.